Gauge Wiring Question....

Here's my newest issue....

Just started happening today. As soon as you turn on the engine, the fuel guage pegs to FULL and the temperature guage pegs HOT. Would this be a short? If so, I would think a short would cut both of them out showing EMPTY and COLD??? Anyone seen this one before and can tell me where to begin? The wiring behind the guage appears normal.

Thanks!!

 

Re: Guage Wiring Question....

anyone?

 

Re: Guage Wiring Question....

Check the electrical grounds -----both for the engine, and the instrument panel.

Have you had the battery out recently, and reversed the polarity when putting it back in???

 

Re: Guage Wiring Question....

Sounds like a short. A fuel gauge when grounded will go to full.

 

Re: Guage Wiring Question....

Not to say it didn't but highly unlikely a short would effect both gauges at the same time. That being said, there is one item that is relative to both gauges and that is the gauge voltage regulator. Sits behind the dash as a small rectangular metal can (usually) and a metal tab holding it to the stud from the dash. Make sure this has a good ground. It is also possible the contacts within the regulator are stuck together which will cause a steady 12v being applied driving the gauges to full scale.

 

Re: Guage Wiring Question....

Still searching. It appears the temp guage has a ground to it and the fuel does not. The battery has not been changed recently. Also, I cannot find that voltage regulator. I would assume it is one the drivers side due to the blower and ducting being mostly on the passanger side, is this correct?

 

The voltage regulator is inside the gauge.

Sent from my HTC Liberty using Tapatalk

 

Re: Guage Wiring Question....

Read this it should walk you through it

http://www.jeeptech.com/electrical/gauges/

 

Re: Guage Wiring Question....

Fuel gauge is not supposed to be grounded. It has a 12v positive feed and the "ground" is provided by the sender. As the float on the sender rises to full it provides less resistance. If you ground the sender wire it should peg the gauge to full.

Here's a page that might be helpful to you: http://www.jeeptech.com/electrical/gauges/

 

Re: Guage Wiring Question....

Sorry about the mis-information. I was under the impression that the external regulator was used on 76 and after but I was proven wrong. The trouble with the gauges should still be with the gauge regulator or the loss of ground between the fuel gauge and the speedo housing or the speedo housing to dash ground.

 

Re: Guage Wiring Question....

I have a few more pdfs if needed

 

Re: Guage Wiring Question....

Love how I do the research and others try and take the credit!!! chainsawguy

Heres another link that may help you

http://street2mud.com/webfiles/Basic Troubleshooting for CJ gauges.pdf

 

Re: Guage Wiring Question....

Could a wire leading back to the gas tank slightly melted to the exhaust cause this?

 

Re: Guage Wiring Question....

yes

 

Re: Guage Wiring Question....

Doubtful, that wire looks like it's to the pressure switch in your brake lines. Unrelated component.

 

Re: Guage Wiring Question....

On the fuel gauge that has the internal regulator, you will have to remove the speedo cluster from the housing before you can see the gauge regulator ground terminal. That ground is required to make the regulator operate. That is also the reason the speedo housing requires a good ground. This ground point is only a contact point. There is no stud or no wire connection to be had.

 

Re: Guage Wiring Question....

http://home.comcast.net/~sday77/binky/images/gauge_scematic.gif

This shows the ground point for the fuel gauge regulator.

 

Re: Guage Wiring Question....

Ha!! Finally had time to play today and bridged the temp guage....works fine. Turns out if the fuel guage goes out they both go out. Who knew? Nice used guage on its way from JW Jeep for $20.

Thank you for all your help and suggestions!!